/*
 * Copyright (C) 2012, 2014-2016 Apple Inc. All rights reserved.
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 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer. 
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 *     notice, this list of conditions and the following disclaimer in the
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 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission. 
 *
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 */

#pragma once

#include "JSScope.h"
#include "PropertyDescriptor.h"
#include "SymbolTable.h"
#include "ThrowScope.h"
#include "include/JavaScriptCore/bytecode/VariableWriteFireDetail.h"

namespace JSC {

    class JSSymbolTableObject : public JSScope {
    public:
        typedef JSScope Base;
        static const unsigned StructureFlags = Base::StructureFlags | OverridesGetPropertyNames;

        SymbolTable *symbolTable() const { return m_symbolTable.get(); }

        JS_EXPORT_PRIVATE static bool deleteProperty(JSCell *, ExecState *, PropertyName);

        JS_EXPORT_PRIVATE static void getOwnNonIndexPropertyNames(JSObject *, ExecState *, PropertyNameArray &, EnumerationMode);

        static ptrdiff_t offsetOfSymbolTable() { return OBJECT_OFFSETOF(JSSymbolTableObject, m_symbolTable); }

    DECLARE_EXPORT_INFO;

    protected:
        JSSymbolTableObject(VM &vm, Structure *structure, JSScope *scope)
                : Base(vm, structure, scope) {
        }

        JSSymbolTableObject(VM &vm, Structure *structure, JSScope *scope, SymbolTable *symbolTable)
                : Base(vm, structure, scope) {
            ASSERT(symbolTable);
            setSymbolTable(vm, symbolTable);
        }

        void setSymbolTable(VM &vm, SymbolTable *symbolTable) {
            ASSERT(!m_symbolTable);
            symbolTable->singletonScope()->notifyWrite(vm, this, "Allocated a scope");
            m_symbolTable.set(vm, this, symbolTable);
        }

        static void visitChildren(JSCell *, SlotVisitor &);

    private:
        WriteBarrier<SymbolTable> m_symbolTable;
    };

    template<typename SymbolTableObjectType>
    inline bool symbolTableGet(
            SymbolTableObjectType *object, PropertyName propertyName, PropertySlot &slot) {
        SymbolTable &symbolTable = *object->symbolTable();
        ConcurrentJSLocker locker(symbolTable.m_lock);
        SymbolTable::Map::iterator iter = symbolTable.find(locker, propertyName.uid());
        if (iter == symbolTable.end(locker))
            return false;
        SymbolTableEntry::Fast entry = iter->value;
        ASSERT(!entry.isNull());

        ScopeOffset offset = entry.scopeOffset();
        // Defend against the inspector asking for a var after it has been optimized out.
        if (!object->isValidScopeOffset(offset))
            return false;

        slot.setValue(object, entry.getAttributes() | DontDelete, object->variableAt(offset).get());
        return true;
    }

    template<typename SymbolTableObjectType>
    inline bool symbolTableGet(
            SymbolTableObjectType *object, PropertyName propertyName, PropertyDescriptor &descriptor) {
        SymbolTable &symbolTable = *object->symbolTable();
        ConcurrentJSLocker locker(symbolTable.m_lock);
        SymbolTable::Map::iterator iter = symbolTable.find(locker, propertyName.uid());
        if (iter == symbolTable.end(locker))
            return false;
        SymbolTableEntry::Fast entry = iter->value;
        ASSERT(!entry.isNull());

        ScopeOffset offset = entry.scopeOffset();
        // Defend against the inspector asking for a var after it has been optimized out.
        if (!object->isValidScopeOffset(offset))
            return false;

        descriptor.setDescriptor(object->variableAt(offset).get(), entry.getAttributes() | DontDelete);
        return true;
    }

    template<typename SymbolTableObjectType>
    inline bool symbolTableGet(
            SymbolTableObjectType *object, PropertyName propertyName, PropertySlot &slot,
            bool &slotIsWriteable) {
        SymbolTable &symbolTable = *object->symbolTable();
        ConcurrentJSLocker locker(symbolTable.m_lock);
        SymbolTable::Map::iterator iter = symbolTable.find(locker, propertyName.uid());
        if (iter == symbolTable.end(locker))
            return false;
        SymbolTableEntry::Fast entry = iter->value;
        ASSERT(!entry.isNull());

        ScopeOffset offset = entry.scopeOffset();
        // Defend against the inspector asking for a var after it has been optimized out.
        if (!object->isValidScopeOffset(offset))
            return false;

        slot.setValue(object, entry.getAttributes() | DontDelete, object->variableAt(offset).get());
        slotIsWriteable = !entry.isReadOnly();
        return true;
    }

    template<typename SymbolTableObjectType>
    ALWAYS_INLINE void
    symbolTablePutTouchWatchpointSet(VM &vm, SymbolTableObjectType *object, PropertyName propertyName, JSValue value, WriteBarrierBase<Unknown> *reg,
                                     WatchpointSet *set) {
        reg->set(vm, object, value);
        if (set)
            VariableWriteFireDetail::touch(vm, set, object, propertyName);
    }

    template<typename SymbolTableObjectType>
    ALWAYS_INLINE void symbolTablePutInvalidateWatchpointSet(VM &vm, SymbolTableObjectType *object, PropertyName propertyName, JSValue value,
                                                             WriteBarrierBase<Unknown> *reg, WatchpointSet *set) {
        reg->set(vm, object, value);
        if (set)
            set->invalidate(vm, VariableWriteFireDetail(object,
                                                        propertyName)); // Don't mess around - if we had found this statically, we would have invalidated it.
    }

    enum class SymbolTablePutMode {
        Touch,
        Invalidate
    };

    template<SymbolTablePutMode symbolTablePutMode, typename SymbolTableObjectType>
    inline bool
    symbolTablePut(SymbolTableObjectType *object, ExecState *exec, PropertyName propertyName, JSValue value, bool shouldThrowReadOnlyError,
                   bool ignoreReadOnlyErrors, bool &putResult) {
        VM &vm = exec->vm();
        auto scope = DECLARE_THROW_SCOPE(vm);

        WatchpointSet *set = nullptr;
        WriteBarrierBase<Unknown> *reg;
        {
            SymbolTable &symbolTable = *object->symbolTable();
            // FIXME: This is very suspicious. We shouldn't need a GC-safe lock here.
            // https://bugs.webkit.org/show_bug.cgi?id=134601
            GCSafeConcurrentJSLocker locker(symbolTable.m_lock, vm.heap);
            SymbolTable::Map::iterator iter = symbolTable.find(locker, propertyName.uid());
            if (iter == symbolTable.end(locker))
                return false;
            bool wasFat;
            SymbolTableEntry::Fast fastEntry = iter->value.getFast(wasFat);
            ASSERT(!fastEntry.isNull());
            if (fastEntry.isReadOnly() && !ignoreReadOnlyErrors) {
                if (shouldThrowReadOnlyError)
                    throwTypeError(exec, scope, ASCIILiteral(ReadonlyPropertyWriteError));
                putResult = false;
                return true;
            }

            ScopeOffset offset = fastEntry.scopeOffset();

            // Defend against the inspector asking for a var after it has been optimized out.
            if (!object->isValidScopeOffset(offset))
                return false;

            set = iter->value.watchpointSet();
            reg = &object->variableAt(offset);
        }
        // I'd prefer we not hold lock while executing barriers, since I prefer to reserve
        // the right for barriers to be able to trigger GC. And I don't want to hold VM
        // locks while GC'ing.
        if (symbolTablePutMode == SymbolTablePutMode::Invalidate)
            symbolTablePutInvalidateWatchpointSet(vm, object, propertyName, value, reg, set);
        else
            symbolTablePutTouchWatchpointSet(vm, object, propertyName, value, reg, set);
        putResult = true;
        return true;
    }

    template<typename SymbolTableObjectType>
    inline bool symbolTablePutTouchWatchpointSet(
            SymbolTableObjectType *object, ExecState *exec, PropertyName propertyName, JSValue value,
            bool shouldThrowReadOnlyError, bool ignoreReadOnlyErrors, bool &putResult) {
        ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(object));
        return symbolTablePut<SymbolTablePutMode::Touch>(object, exec, propertyName, value, shouldThrowReadOnlyError, ignoreReadOnlyErrors,
                                                         putResult);
    }

    template<typename SymbolTableObjectType>
    inline bool symbolTablePutInvalidateWatchpointSet(
            SymbolTableObjectType *object, ExecState *exec, PropertyName propertyName, JSValue value,
            bool shouldThrowReadOnlyError, bool ignoreReadOnlyErrors, bool &putResult) {
        ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(object));
        return symbolTablePut<SymbolTablePutMode::Invalidate>(object, exec, propertyName, value, shouldThrowReadOnlyError, ignoreReadOnlyErrors,
                                                              putResult);
    }

} // namespace JSC
